桂林市腹泻病源沙门菌表型特征及分子分型研究

Study on the phenotypic characteristics and molecular typing of Salmonella strains responsible for diarrhea in Guilin

目的了解2021年桂林市腹泻病源沙门菌菌株表型特征及分子分型特征,建立相关数据库,为桂林市控制沙门菌引起的腹泻病传播和疫情溯源提供实验室有效数据。方法通过对菌株进行血清学鉴定、脉冲场凝胶电泳(pulsed field gel electrophoresis,PFGE)试验和药物敏感试验3类项目检测,采用国家致病菌识别网信息化平台系统对其结果进行关联研究,确定菌株间的亲缘性。结果2021年来自桂林市3家医院患者的42株沙门菌经生化鉴定及血清凝集试验,得到了11种血清型,其中优势菌有鼠伤寒沙门菌(17株)、伦敦沙门菌(7株)和肠炎沙门菌(5株);药物敏感试验结果显示(16种抗生素):氨苄西林(ampicillin,AMP)(61.90%)耐药率最高,其次是复方新诺明(sulfamethoxazole,SXT)(59.52%)。多粘菌素E(colistin E,ECT)、美罗培南(meropenem,MEM)、厄他培南(ertapenem,ETP)、替加环素(tigecycline,TIG)、阿米卡星(amikacin,AMI)5种为敏感药物,敏感率均为100.00%。多重耐药菌株有28株(66.67%),最多见是4耐药物,耐药谱为氯霉素(chloramphenicol,CHL)-复方新诺明(SXT)-四环素(TET)-氨苄西林(AMP)(7株);耐药种类最高的是8耐,耐药谱为氯霉素(CHL)-复方新诺明(SXT)-头孢噻肟(cefotaxime,CTX)-四环素(TET)-环丙沙星(ciprofloxacin,CIP)-萘啶酸(nalidixic acid,NAL)-氨苄西林(AMP)-氨苄西林/舒巴坦(ampi⁃cillin/sulbactam,AMS);42株沙门菌经过聚类分析可分为38种带型图谱,显示出较大的遗传多样性。结论2021年桂林市腹泻病源沙门菌的血清型主要以鼠伤寒沙门菌、伦敦沙门菌和肠炎沙门菌为主,耐药状况和多重耐药率不容乐观,PFGE带型图谱呈遗传多样性,血清型、耐药谱与PFGE分型无明显关联。

Objective To understand the phenotypic and molecular characteristics of Salmonella strains causing diarrhea in Guilin in 2021,and to establish relevant database,so as to provide effective laboratory data for controlling the transmission of diarrhea caused by Salmonella and tracing the epidemic source in Guilin.Methods Three types of tests were conducted on the strains,including serological identification,pulsed field gel electrophoresis(PFGE)test and drug sensitivity test.The results were correlated with the information platform system of the National Pathogenic bacteria Identification Network to determine the affinity between the strains.Results In 2021,42 strains of Salmonella from patients in 3 hospitals in Guilin were identified by biochemical identification and serum agglutination test,and 11 serotypes were obtained,among which the dominant bacteria were Salmonella typhimurium(17 strains),Salmonella londonii(7 strains)and Salmonella enteritidis(5 strains).The results of drug sensitivity test showed that(16 antibiotics):the drug resistance rate to ampicillin(AMP)(61.90%)was the highest,followed by sulfamethoxazole(SXT)(59.52%).Five sensitive drugs were colistin E(ECT),meropenem(MEM),ertapenem(ETP),tigecycline(TIG)and amikacin(AMI),with a sensitivity rate of 100.00%.There were 28 multidrug-resistant strains(66.67%),and the most common was 4-drug resistant,with a resistance spectrum of chloramphenicol(CHL)-sulfamethoxazole(SXT)-tetracycline(TET)-ampicillin(AMP)(7 strains).The highest resistance types were 8 resistance,and the resistance spectrum was chloramphenicol(CHL)-serofloxacin(SXT)-cefotaxime(CTX)-tetracycline(TET)-ciprofloxacin(CIP)-nalidixic acid(NAL)-ampicillin(AMP)-ampicillin/sulbactam(AMS).After cluster analysis,42 strains of Salmonella could be divided into 38 types of band pattern,showing great genetic diversity.Conclusion The Salmonella typhimurium,Salmonella London and Salmonella enteritidis are the main serotypes of Salmonella diarrhea diseases in Guilin in 2021.The drug resistance status and multiple drug resistance rate are not optimistic.The PFGE band pattern shows genetic diversity,and there is no significant correlation between serotypes,drug resistance spectrum and PFGE typing.